1. Field of the Invention
The present invention relates to a method of manufacturing a thin film transistor array substrate, and more particularly, to a method of manufacturing a thin film transistor array substrate incorporating a photo sensor.
2. Description of Related Art
With the popularity of liquid crystal and plasma displays, flat panel displays have become the so-called “multimedia board” in addition to being used for displaying images. A new development focus of the current display technology is to integrate an ambient light sensing capability in the flat panel display, which mainly is to build a photo sensor in the flat panel display in order to detect intensity of ambient light.
A current and common ambient light sensing technology is to form a p-i-n (P-type doped silicon/undoped silicon/N-type doped silicon) photo sensor on a glass substrate of a display panel through a low temperature poly-silicon (LTPS) process. However, due to limitation of the process, the p-i-n photo sensor manufactured through the LTPS process has a problem of poor photoelectric effect because of insufficient thickness of the poly-silicon film and lower sensitivity. In addition, light from a backlight source directly irradiates the p-i-n photo sensor through the glass substrate and thereby affects the photo sensing characteristics of the p-i-n photo sensor and reduces a signal to noise ratio (SNR) of a photo sensing signal, causing distortion of measurement results.